Abstract: A filter assembly for a servo valve that includes a first fluid nozzle defining a first fluid passage therethrough between a first fluid inlet and a first fluid outlet and a second fluid nozzle defining a second fluid passage therethrough between a second fluid inlet and a second fluid outlet. The first and second fluid nozzles arranged in end to end abutment with each other to form a tubular fluid nozzle unit in which the first and second fluid inlets are adjacent each other, and the first and second fluid passages align to form a common fluid passage through the tubular fluid nozzle unit. The first fluid outlet is at a first end of the tubular fluid nozzle unit and the second fluid passage being at a second, end of the tubular fluid nozzle unit.

Abstract: A magnetic core structure for a Linear Variable Differential Transducer (LVDT) comprising an elongate core of magnetic material mounted within a protective tube and means for positioning the core within the protective tube, the means for positioning comprising a ball provided within the protective tube at one end of the core, the ball being formed of an elastic material having a coefficient of thermal expansion selected to compensate the difference in elongation between magnetic core structure components caused by thermal expansion.

Abstract: A magnetic core structure for a Linear Variable Differential Transducer (LVDT) comprising an elongate core of magnetic material mounted within a protective tube and means for positioning the core within the protective tube, the means for positioning comprising a ball provided within the protective tube at one end of the core, the ball being formed of an elastic material having a coefficient of thermal expansion selected to compensate the difference in elongation between magnetic core structure components caused by thermal expansion.

Abstract: A valve assembly for an active clearance control (ACC) system in a gas turbine engine. The assembly comprises a first valve disc positioned within a first outlet duct, a second valve disc positioned within the second outlet duct, and a shaft coupled to the first and second valve discs such that rotation of the shaft rotates both the first and second valve discs within the first and second outlet ducts, respectively. A flow control member in the second outlet duct surrounds the second valve disc, and is configured to restrict fluid flow passing through the second outlet duct to a greater extent than the fluid flow passing through the first outlet duct for a given degree of rotation of the first and second valve discs. A corresponding ACC system, gas turbine and method is also provided.

Abstract: A linear variable differential transducer (LVDT) includes a primary coil, a first secondary coil, and a second secondary coil. Each of the first and second secondary coils comprises a wound portion that is wound around a longitudinal axis of the LVDT, and first and second non-wound portions at either end of the wound portion. The wound portion meets the first and second non-wound portions at locations that are separated from each other in a direction along the longitudinal axis.

Abstract: A servovalve comprising: a fluid transfer valve assembly comprising a supply port and a control port; a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a drive member configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow.

Abstract: A metering valve comprising a solenoid having: a coil mounted on a core; and an armature moveable axially with respect to the core and against a return bias in response to a current in the coil; a variable capacitor having a first plate mounted for movement with the armature and a second plate fixed with respect to the core. The metering valve comprises an electronic feedback loop which is used to adjust the current in the coil based on a feedback signal derived from of the capacitance of the variable capacitor. A reference capacitor may be provided having opposing third and fourth plates at a set separation. A valve body may house the solenoid, the variable capacitor and the reference capacitor.

Abstract: There is provided a pole piece for a torque motor, wherein the pole piece is formed at least partially by two arcuate members extending in opposite directions and following a generally circular path defining a perimeter of the pole piece, wherein the arcuate members meet each other at diametrically opposed attachment portions of the pole piece.

Abstract: A spool assembly for a second stage of a servo valve comprises a spool having an axis (L) and an opening for a feedback member provided in a central region of the spool extending perpendicular to the axis. An adjustable joint is provided within the spool for securing a feedback member relative to the spool, comprising first and second jaw arms being displaceable relative to each other along the axis of the spool. The jaw arms have opposing clamping surfaces, wherein the clamping surfaces are arranged to be drawn towards each other as the jaw arms are drawn away from each other, such that a feedback member can be clamped between the opposed clamping surfaces of the jaw arms and thereby secured relative to the spool.

Abstract: A servovalve comprising: a fluid transfer valve assembly comprising a supply port and a control port; a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a drive member configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow.

Abstract: A metering valve comprising a solenoid having: a coil mounted on a core; and an armature moveable axially with respect to the core and against a return bias in response to a current in the coil; a variable capacitor having a first plate mounted for movement with the armature and a second plate fixed with respect to the core. The metering valve comprises an electronic feedback loop which is used to adjust the current in the coil based on a feedback signal derived from of the capacitance of the variable capacitor. A reference capacitor may be provided having opposing third and fourth plates at a set separation. A valve body may house the solenoid, the variable capacitor and the reference capacitor.